Project Summary There is overwhelming and rapidly increasing evidence for the involvement of MCP-1 in pathophysiological processes that play critical roles in the development of cardiovascular diseases. MCP-1 binds to its receptor and initiates signaling cascade that results in not only chemotaxis but also induction of gene expression changes. The nature of the gene expression changes and their role in pathogenesis are poorly understood. Our research is aimed at filling this void. We discovered that MCP-1 induces the first member of a novel family of CCCH-Zn finger transcription factors, we call MCP-1 induced protein, MCPIP. On the basis of suggestive experimental evidence we postulate that MCPIP and a set of novel genes induced by it are involved in cell death that play a critical role in the development of heart failure. We propose to test this hypothesis. We postulate that MCPIP cause production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) that cause ER stress. Prolonged ER stress caused by sustained expression of MCPIP will lead to autophagy and cell death. Elucidation of the mechanisms by which MCPIP mediates these pathophysiological processes can reveal novel steps suitable for therapeutic intervention in the development of heart failure. To achieve this long term objective we will pursue the following specific aims: Specific Aim 1. Test the hypothesis that MCPIP induces the production of ROS and RNS that causes ER stress and that the prolonged ER stress resulting from the sustained MCPIP expression leads to autophagy and cell death in cardiomyoblast cell line, H9c2. Identify the key players involved in the progression of these events and validate the key findings in CMC isolated from neonatal hearts. Specific Aim 2. Test whether the MCPIP mediates production ROS/RNS, ER stress, autophagy and cell death and thus cause development of heart failure in mice. a) Determine whether CMC-targeted expression of MCPIP induces oxidative and ER stress, cell death and heart failure in mice and if it does, determine whether specific inhibitors of ER stress attenuates MCPIP-induced heart failure in MCPIP- mice. b) Determine whether MCPIP knockout attenuates oxidative and ER stress, cell death and the development of heart failure caused by CMC-targeted expression of MCP-1.